This application is related to a hole coring system for forming a hole in a substrate such as concrete.
U.S. Pat. No. 7,484,578 ('578 patent), issued to Warren Duncan of U.S. Saws, Inc. discloses a unique and beneficial way of forming a hole in a substrate. Conventionally, a hole is formed in concrete through the use of a drill press like device such as a drill rig. Initially, the location of the hole in the substrate is located. The drill press is attached to the substrate adjacent the hole with a chuck of the drill press disposed over the center of the hole to be cut. A concrete hole drilling bit is secured to the chuck of the drill press after the drill press is securely attached to the substrate. The drill bit is rotated by the drill press and a handle of the drill press is rotated to push the drill bit toward the substrate for forming the hole in the substrate. Unfortunately, in this scenario, the drill press does not apply an even load on the drill bit due to the nonsymmetrical setup. The device disclosed in the '578 patent uniquely applies downward pressure to the drill bit from a guide post centrally located at the location of the substrate to be cut and asymmetrically aligned to the rotating axis of the drill bit.
For larger holes, a stabilizing arm is used. This embodiment is disclosed in U.S. patent application Ser. No. 12/009,169 ('169 application), now U.S. Pat. No. 7,658,242, filed on Jan. 17, 2008, the entire contents of which is expressly incorporated herein by reference. The '169 application is a continuation-in-part application of the application which matured into the '578 patent. The stabilizing arm is shown in FIG. 25 of the '169 application. Unfortunately, the stabilizing arm is very bulky and requires the user to hold the stabilizing arm during the drilling operation. As a workaround, a brace may be secured nearby to hold the stabilizing arm. However, the brace and the stabilizing arm require an extra setup thus making the hole coring system a bit cumbersome and inconvenient. Also, a counter reaction force to the force on the arm or brace provides a side load on the post of the drilling system thereby bending the post. Moreover, any spikes in the load creates spikes in the torque which may cause the drilling system to undesirably vibrate.